Mobile Device

ABSTRACT

Mobile apparatus, comprising a main frame ( 202 ) displaceable on displacing means; a sub-frame ( 203 ) which is rotatable around a vertical axis and which is mounted on the main frame and provided with a control unit; at least one operating arm ( 210 ) mounted on the sub-frame and an automatically movable lifting device provided on the main frame, which lifting device is adapted to be connectable to an agricultural attachment.

The present invention relates to a mobile apparatus for use inagriculture, forestry, in earth-moving and other operations such aspulling and driving farm machinery, digging and loading, lifting anddisplacing loads and so on. The present invention relates moreparticularly to a mobile apparatus which can perform more of thesetasks, optionally simultaneously.

Known from the prior art are tractors which are typically provided witha three-point mounting for mounting a plough or other attachmentsthereon. Further known are so-called backhoe loaders which provide anexcavator-loader combination on wheels. A backhoe loader is a vehiclesimilar to a tractor and having at the rear a digging arm and at thefront a loading bucket. Finally, numerous excavators are known in whicha digging arm is mounted on a rotatable sub-frame of the excavator.

The present invention has for its object to provide a mobile apparatusof the type stated in the preamble which allows more of the above statedtasks to be performed, optionally simultaneously, in practical mannerusing one and the same mobile apparatus.

The present invention is distinguished for this purpose in that themobile apparatus comprises:

-   -   a main frame displaceable on displacing means;    -   a sub-frame which is rotatable around a vertical axis and which        is mounted on the main frame and provided with a control unit;    -   at least one operating arm mounted on this sub-frame; and    -   an automatically movable lifting device provided on the main        frame, which lifting device is adapted to be connectable to an        agricultural attachment. The lifting device is preferably a        three-point lifting device.

The mobile apparatus can in this way be used for normal agriculturalactivities wherein a suitable agricultural attachment can be coupled tothe lifting device while the operating arm mounted on the sub-frame canbe used, optionally simultaneously, for other operations, typicallydigging/loading operations.

The multifunctional tractors of the prior art do not have a rotatablesub-frame and the operating arm must typically be uncoupled before anattachment coupled to the three-point lifting device can be used. Thisproblem is solved by the invention by mounting the operating arm on arotatable sub-frame while the lifting device is provided on the mainframe.

The term “three-point lifting device” must be understood to mean a usualthree-point lifting device as known on tractors, this three-pointlifting device also been referred to with the terms three-pointsuspension or three-point coupling.

According to the preferred embodiment, the at least one operating armcomprises an articulated operating arm, and in particular a digging armon the outer end of which an attachment can be mounted. The articulatedoperating arm more preferably consists of at least three articulationsconnected pivotally to each other, wherein the last articulation of theoperating arm has a greater length than the penultimate one such thatthe articulations can be folded against each other, and the arm can betransformed from an articulated arm to a single lifting arm. Suchembodiments are described in detail in the European patent EP 1 472 416in the name of applicant, the text of which is incorporated herein byreference.

Other possible embodiments of the articulated arm are described in theEuropean patents EP 1 245 739, EP 0 740 023 and EP 1 818 460 in the nameof the Group Mecalac, and in the French patent FR 2 727 998, likewise inthe name of Mecalac.

According to another possible embodiment, the at least one operating armcomprises a lifting arm, for instance a single or stereo/double arm. Theat least one operating arm can further take a telescopic form.

According to a further aspect of the invention, the at least oneoperating arm can be mounted on the sub-frame for pivoting around ahorizontal axis and/or a vertical axis. Such an assembly is likewisedescribed in the above stated patent in the name of applicant, see inparticular FIG. 4 and the related description.

According to the preferred embodiment, the mobile apparatus is atractor. Within the scope of the present invention the term “tractor”must be interpreted broadly as a vehicle which can pull, push or towsomething not having a drive of its own. Although the displacing meansof a tractor are typically wheels, it is also possible in respect of thepresent invention to envisage caterpillar tracks or mechanical legs.

The mobile apparatus typically comprises one or more motors for drivingthe displacing means, the at least one operating arm and the liftingdevice. Examples of possible drive means are: petrol, diesel, biodiesel,ethanol, LPG, natural gas, hydrogen or electric motors; fuel cells,batteries etc., or a combination thereof. In the case of an embodimentwith wheels, these can be steerable and/or driven. According to apossible embodiment, only a number of the wheels are steered and/ordriven.

According to yet another aspect, the main frame can have a so-calledarticulated steering which is typical for tractors, wheel loaders andloading buckets used in forestry or road construction. With anarticulated steering a mobile apparatus can rotate in the middle,whereby it is possible to negotiate very tight bends. The rotation ismade possible by a vertical or substantially vertical axis usuallypositioned between the axes of the wheels/caterpillar tracks. Four-wheelsteering is also possible.

In the case of a caterpillar track drive, the invention comprisesembodiments with two caterpillar tracks, but also embodiments with aplurality of caterpillar tracks, wherein for instance in an embodimentwith wheels each of the wheels is replaced by a caterpillar track.

According to preferred embodiment, the drive means are mounted in thesub-frame. In the case of a motor, the motor will typically be mountedat the bottom of the sub-frame, while the fuel tank connected theretocan be mounted in the sub-frame or in the main frame.

According to a possible embodiment, the motor is mounted centrally atthe rear of the sub-frame and a tank is mounted on either side thereof,which tank can be intended for fuel, hydraulic oil or any other liquidor gas necessary for driving. Other variants will be discussedhereinbelow with reference to the figures.

According to preferred embodiment of the invention, a feed for liquidand/or gas and/or electricity rotatable through 360° is provided betweenthe rotatably mounted sub-frame and the main frame such that the liftingdevice, the displacing means and optional other components can beprovided with the necessary energy. This energy can also be supplied tothe different attachments via couplings close to the lifting device,often at the rear of the main frame or the sub-frame, although the frontside is also an option.

The sub-frame is preferably provided with a driver's seat situatedsubstantially in the centre, i.e. at half the width of the machine. Inthis way an operator will have a good view of the operations performedby the at least one operating arm. According to another possibility, theposition of the operator can also be placed out of the centre, see forinstance the embodiments described in the above stated patent in thename of applicant. The skilled person will appreciate that embodimentscan likewise be envisaged without operator, wherein the mobile apparatusis remotely controlled.

According to a possible embodiment, the at least one operating arm isactuated as described in the Netherlands patent NL 1 028 661 in the nameof applicant. The skilled person will once again appreciate thatnumerous other actuations are possible in accordance with the embodimentof the at least one operating arm.

In the case of a sub-frame with driver's seat, this can be embodiedoptionally with rollover protection, with a cab, with a fold-away orpartially fold-away cab or with a convertible cab.

According to the preferred embodiment of the invention, the main frameis further provided with one or more stabilizers such as jacks for thepurpose of stabilizing the apparatus during specific operations, and inparticular during the use of the at least one operating arm. Accordingto one option, two stabilizers are provided at the rear which can beactuated via one or more actuating members such as hydraulic cylinders.

According to a further developed embodiment, the stabilizers and thelifting device are combined, preferably at the rear, wherein forinstance a shared actuation is provided for the lifting device and theone or more stabilizers. The stabilizers are preferably removable, thissuch that the stabilizer can be removed or can be made more compact, andso leave space for agricultural attachments coupled to the liftingdevice.

An embodiment of the mobile apparatus can further be embodied with oneor more stabilizers on the front side. According to a possibleembodiment, a stabilizing element is provided on the front side whichcan be connected to an attachment, typically a loading bucket, whichattachment can in this way function as stabilizing means, particularlyon a soft ground surface.

According to yet another variant, a stabilizer can be formed by couplingan attachment such as a loading bucket to a quick change systemconnected to the main frame, this such that the quick change system withattachment forms a stabilizing platform. Such a quick change system canbe of the same type as the system used on the outer end of operatingarms for the purpose of coupling a digging or loading attachmentthereto. It is also possible to use an adapter or quick change system ofthe skid steer of bobcat type, for instance in accordance with the SAE J2513 norm.

According to the preferred embodiment of the mobile apparatus, thecentre of gravity of the displaceable main frame lies lower than the topside of the displacing means, and the sub-frame has an underside with arecess, the form of which is adapted to extend over the displacingmeans, this such that the lowest point of the sub-frame lies lower thanthe top side of the displacing means and that the sub-frame can rotatefreely without making contact with the displacing means. Such a designresults in a stable mobile apparatus in which the rotatable sub-framelies as low as possible, this in contrast to the prior art diggingmachines in which the rotatable sub-frame typically lies higher than thedisplacing means.

According to the embodiment in the form of a typical tractor with rearwheels which are larger than the front wheels, the main frame ispreferably situated substantially between the front and rear wheels andthe sub-frame has an underside with a recess, the form of which isadapted to extend over the rear wheels. The rotatable sub-frame willtypically be embodied with a counterweight which can play a part asintegrated wing or can function as a body in which a tank or a batterycan be accommodated.

According to a further developed embodiment, the at least one operatingarm is provided with a guiding adapted to move the attachment over asurface for working. In this way a loading bucket can follow thecontours of the ground surface, this resulting in a tidy, smooth andefficient working.

It is further recommended to block the sub-frame relative to the mainframe in specific situations, for instance:

-   -   in an operative position of the at least one operating arm,        typically a digging or load bucket position in the case of a        digging/loading operating arm;    -   in a situation wherein the operating arm threatens to rotate        against a part of the main frame or the displacing means (in        another variant the operating arm is automatically moved        upward).

According to a further aspect of the invention, a control system can beprovided for automatically guiding the rotation of the sub-frame and/orthe movement of the at least one operating arm as a function of thesteering of the displacing means. In this way the operating arm can forinstance be placed automatically in the same direction as the traveldirection. According to a further developed embodiment, the angle whichthe operating arm makes can be the same as the steering wheel movement,or be proportional to the steering wheel movement optionally as afunction of the travel speed of the machine.

According to an embodiment, the mobile apparatus is provided on a frontside with a pair of front wheels and on a rear side with a pair of rearwheels, wherein the front wheels are larger than or as large as the rearwheels.

According to an embodiment, the lifting device is provided on the frontside or on the rear side, or on both the front side and the rear side.

According to an embodiment, the rear side is provided with a couplingsystem to which a counterweight, in particular a loading bucket, can becoupled.

According to an embodiment, the apparatus has a front side and rear sideand a travel direction corresponding thereto, wherein the traveldirection, and therefore also the front and rear sides, are reversible.

According to an embodiment, a switch which can be operated by a driveris provided for adjusting the travel direction.

According to an embodiment, the mobile apparatus is provided withsteering means, such as a steering wheel or a joystick, wherein a signalmanipulator such as a relay is further provided, which signalmanipulator is coupled to the switch and to the steering means forcontrolling a steering member for moving the mobile apparatus in thetravel direction set by the driver using the switch.

According to an embodiment, the mobile apparatus is provided with aforward/reverse switch, wherein the forward/reverse switch is likewisecoupled to the signal manipulator for controlling the steering memberfor moving the mobile apparatus in the travel direction set by thedriver using the switch, taking into account the position of theforward/reverse switch.

According to an embodiment, an additional attachment such as a mowingbar is mounted under the main frame.

According to an embodiment, the front and rear wheels operate at adifferent track width.

According to an embodiment, the track width of the wheels is adjustableand means for adjusting the track width are provided which can beoperated by a driver.

According to an embodiment, braking and/or locking means are providedfor limiting and/or locking the movement of the sub-frame relative tothe main frame.

The present invention will be further elucidated on the basis of anumber of non-limitative exemplary embodiments with reference to theaccompanying drawing, in which:

FIGS. 1A to 1E show respectively a left side view, a rear view, a frontview, a right side view and a top view of a first embodiment of a mobileapparatus according to the invention.

FIGS. 2A to 2D show different digging positions of an articulated arm ofa second embodiment of a mobile apparatus according to the invention;

FIGS. 3A and 3B show a third embodiment of a mobile apparatus accordingto the invention, wherein agricultural attachments are coupled at thefront and rear;

FIG. 4A shows a fourth embodiment, wherein a trailer is coupled at therear;

FIG. 4B shows a fourth embodiment with a telescopic loading bucket arm;

FIG. 5 shows a fifth embodiment with a digger bucket at the rear, thisdigger bucket being attached to the three-point lifting device;

FIGS. 6A to C show a sixth embodiment in which quick change systems areprovided at the outer end of the operating arm and on the front side ofthe main frame;

FIG. 7 shows a seventh embodiment with an operating arm with loadingbucket;

FIG. 8 illustrates a top view of an eighth embodiment with four-wheelsteering;

FIGS. 9A and 9B illustrate a ninth embodiment with an adapter;

FIG. 10 shows a side view of a tenth embodiment;

FIGS. 11A to 11C show respectively a schematic top view, side view andrear view of an eleventh embodiment according to the present invention,in which the location of the drive means is illustrated;

FIG. 12 shows a top view of a twelfth embodiment;

FIGS. 13A to 13C show respectively a schematic top view, side view andrear view of a thirteenth embodiment according to the present invention;

FIGS. 14A and B show respectively a top view and a side view of afourteenth embodiment in which a hybrid drive is used;

FIGS. 15A, B and C show respectively a top view, side view and rear viewof a fifteenth embodiment according to the present invention;

FIGS. 16A and 16B show respectively a top view and side view of asixteenth embodiment;

FIGS. 17A to 17C show respectively a top view, a side view and a rearview of a seventeenth embodiment in which a fuel cell is used;

FIGS. 18A to 18C show respectively a top view, side view and rear viewof an eighteenth embodiment;

FIGS. 19A to C show respectively a top view, side view and rear view ofa nineteenth embodiment;

FIGS. 20A and B show respectively a top view and rear view of atwentieth embodiment;

FIGS. 21(A),(B),(C),(D),(E) show respectively a side view, a top view, atop view of a variant, a perspective view as seen from the front and aperspective view as seen from the rear of a twenty-first embodiment;

FIG. 22 shows a side view of a twenty-second embodiment;

FIG. 23 shows a side view of a twenty-third embodiment;

FIG. 24 shows a side view of the twenty-fourth embodiment;

FIG. 25(A) illustrates schematically the switching of the traveldirection; and

FIG. 25(B) illustrates schematically the switching of the traveldirection and from forward to reverse.

FIGS. 1A to 1E show a first embodiment of a mobile apparatus accordingto the invention in the form of a tractor. Mobile apparatus 1 comprisesa main frame 2 displaceable on wheels 4 and a sub-frame 3 mountedthereon for rotation round a vertical axis. Sub-frame 3 is provided witha driver's seat 5 and a number of steering elements, including joysticks7, a steering wheel 6 and pedals 15. Main frame 2 is preferably situatedas low as possible and in the shown embodiment lies substantially lowerthan the top side of front and rear wheels 4. Sub-frame 3 has a bottomside which lies lower than the top side of rear wheels 4 and is designedsuch that the sub-frame extends above rear wheels 4, wherein a recess 16is provided in the bottom side such that the sub-frame can rotate freelywithout making contact with wheels 4.

As shown best in FIG. 1B and FIG. 1E, main frame 2 is provided on therear side with a three-point lifting device. Such a lifting device isstandard in agriculture and generally known to the skilled person, sodetailed description thereof is not necessary. Further provided on therear side of main frame 2 is a power takeoff shaft 12 (see FIG. 1B). Inthis way attachments coupled to the power takeoff can also be driven bythe motor of the mobile apparatus. Such a power takeoff is generallyknown and will not be discussed in detail here. Note that such a powertakeoff can also be provided on the front side of the mobile apparatus.A tow-hook 24 is further provided on the rear side of main frame 202.

An operating arm 10 with an attachment 11 is further mounted onsub-frame 3. In the shown embodiment operating arm 10 consists of anarticulated arm on which a loading bucket 11 is mounted. Thearticulations of operating arm 10 are moved using a number of cylinders17. The lower cylinder 17 is connected to the sub-frame by means ofadjusting device 18. Attachment 11 is connected via a parallelogramhinge 19 to last cylinder 17. In this way the position of the attachmentcan be adjusted relative to the last articulation. Adjusting device 18is used to optimize the geometry of actuating member 17 (or theactuating members in a multiple variant) relative to the articulation.In the loading bucket position (lowest position) the articulation candescend further downward due to the adjusting device and in the diggingposition (uppermost position) the articulation can be moved higher. Theangle which the actuating member makes with the arm is then also betterin the two different positions and thereby produces more force.

As shown best in FIGS. 1B and 1E, the main frame is provided at the rearwith two stabilizers 14 in the form of jacks. These stabilizers arepreferably partially removable. In the shown embodiment the part of thejack located on the outside is slidable into a part of the jack lyingcloser to main frame 2, whereby the jack can be made shorter so as toleave space for agricultural attachments when they are coupled tothree-point lifting device 13 or to power takeoff 12. Control members 20are further provided for moving jacks 14.

FIGS. 2A to 2D show a second embodiment of a mobile apparatus accordingto the invention in four different positions. Similar components aredesignated with the same reference numeral, wherein 200 is added.Operating arm 210 has three articulations: 221, 222, 223 which aremovable relative to each other using cylinders 217. Lower cylinder 217is connected to sub-frame 203 using an adjusting device 218. In FIG. 2Athe adjusting device is placed in the highest position. Provided at therear of main frame 202 are stabilizers 214 embodied as described withreference to FIGS. 1A to 1E. At the front of main frame 202 anadditional stabilizer 214′ is provided in the form of a loading bucketconnected to a control member 220′. The loading bucket is in this waygiven a useful function when it is not in use. FIG. 2B shows a positionin which sub-frame 203 is rotated through about 90° such that operatingarm 210 is situated at the side of the mobile apparatus. The arm issituated here in a digging position. FIG. 2B further shows clearly thatsub-frame 203 is provided with a recess 216 which allows free rotationof the sub-frame while the bottom side of the sub-frame liesconsiderably lower than the top side of the rear wheels of the mobileapparatus. The geometry of adjusting device 218 is further typicallyadapted to the geometry of the sub-frame such that they do not makecontact with each other during rotation.

As best shown in FIG. 2D, sub-frame 203 is preferably dimensioned suchthat the counterweight in the form of a wing on the rear side of thesub-frame (see no. 213) extends substantially no further than jacks 214.In this way the mobile apparatus remains completely stable duringdigging.

FIG. 2C further shows the position in which sub-frame 203 is rotatedthrough 180° such that the digging arm is situated on the rear side ofthe mobile apparatus. In this way the second embodiment according to theinvention can be used as a backhoe loader. Finally, FIG. 2D showssub-frame 203 rotated through substantially 90° to the other sidecompared to FIG. 2B.

FIGS. 3A and 3B show a third embodiment of a mobile apparatus accordingto the invention in which agricultural attachments are coupled on thefront and rear side. The same reference numerals as in FIGS. 1A to 1Eare once again used, wherein 300 is added. On the front side anagricultural attachment 326 is coupled to the outer end of operating arm310. Operating arm 310 is connected to sub-frame 303 which is rotatablymounted on main frame 302. At the rear of the mobile apparatus anagricultural attachment 325 is connected to the three-point liftingdevice 313. Agricultural attachment 325 is further driven via powertakeoff 312.

FIG. 4A shows a fourth embodiment wherein a trailer 427 is connected totow-hook 424. FIG. 4B shows the same embodiment without trailer, with anoperating arm 410 in the form of a telescopic arm with two parts 421,422 which can slide into each other. An attachment 411 is coupled to theouter end of telescopic arm 410.

FIG. 5 shows a fifth embodiment with a digger bucket 528 connected atthe rear to main frame 502. When the machine is in the load bucketposition (wherein the operating arm functions as a single lifting armwith a loading bucket 511 on its outer end) and is used as loadingbucket or so-called tool carrier, it can then be useful to also carrythe digger bucket 528 at the same time. It may after all be the casethat digging will once again be necessary at another location on theworkplace. Digger bucket 528 can then be readily uncoupled and mountedonce again on the operating arm. During digging the loading bucket 511can be used as support point at the front, see FIG. 2A. The liftingdevice therefore has solely the function as support here, although thisis now useful since the lifting device can itself also lift the bucket.

FIGS. 6A to 6C further show an embodiment with yet another variant of astabilizer on the front side. The front side is provided with a quickchange system 629 to which an attachment can be coupled. Quick changesystem 629 is controlled using a control member 629′. In FIGS. 6B and 6Ccan be seen how a bucket 614′ can be used as extra stabilizer on thefront side.

FIG. 7 shows a seventh embodiment which is the same as the firstembodiment, with the difference that a loading bucket 711 is coupled tooperating arm 710, wherein the operating arm is in the folded positionand therefore functions as a single lifting arm.

FIG. 8 shows an embodiment with steered front and rear wheels 804, 804′.FIG. 8 further illustrates how sub-frame 803 co-rotates in the steeringdirection of the front wheels. The skilled person will appreciate thatthis co-rotation can further depend on other variables in addition tothe direction of the front wheels.

FIGS. 9A and 9B show a ninth embodiment in which an adapter is mountedon the quick change system. Such an adapter 930 allows the mounting ofother attachments. Other attachments are for instance: attachments usedmainly on skid steers, such as a driven snow shovel, a rotating brush, adozer blade, a concrete mixer and so on.

According to a variant the machine has no adapter, but the attachmentsare then mounted via a separate quick change system.

Finally, FIG. 10 shows an embodiment with a normal digging arm 1010 witha first guide 1021 in the form of a curved arm.

FIGS. 11A to C illustrate the arrangement of the different componentsnecessary for driving the wheels and the operating arm and possibleother components such as the stabilizers, the power takeoff etc. in anembodiment of a mobile apparatus according to the invention. As shown inFIG. 11A, motor 1244 is arranged centrally in sub-frame 1203. Tanks1241, 1242 are arranged on either side of motor 1244. Such a tank canfor instance be intended for storing hydraulic oil or for storing fuelor for storing another liquid or gas. Motor 1244 is typically acombustion engine but can also be any other type of motor. One or morepumps 1240, typically liquid pumps, can further be provided in sub-frame1203. A cooling element or radiator 1243 is also provided on the rearside of motor 1244. A feed 1245 rotatable through 360° for liquid and/orgas and/or electricity lines is provided between sub-frame 1203 and mainframe 1202.

As best shown in FIGS. 11B and 11C, the motor is preferably mounted aslow as possible in sub-frame 1203. A great stability is in this wayobtained.

FIG. 12 illustrates another possible embodiment in which elements 1241to 1244 are arranged at a determined angle compared to the embodiment ofFIGS. 11A to C.

FIGS. 13A to C illustrate another variant for arranging the drive meansin an embodiment of the mobile apparatus according to the invention. Inthis embodiment tanks 1341, 1342 are placed further forward and acooling element 1343 and pumps 1340 are arranged on either side of motor1344. Such an embodiment will once again result in a stableconstruction.

FIGS. 14A and B show an embodiment similar to that in FIGS. 13A to C,but for a hybrid drive. Tanks 1441 and 1442 are here liquid or gas tanksand, in addition to liquid pump 1440, an additional drive unit, forinstance a generator unit 1447, is provided. Further provided is astorage capacity for electricity such as a battery 1446.

FIGS. 15A to C show a hybrid drive unit, the components of which aredistributed over the sub-frame and the main frame. In the shownembodiment motor 1544 is arranged in the sub-frame, while tanks 1541 and1542 are arranged in the main frame. Pump 1540, generator unit 1547 andthe electricity storage capacity 1546 are further likewise accommodatedin the sub-frame.

FIGS. 16A and B show an embodiment of a drive with a fuel cell in whichthe fuel cell is stored either centrally 1648 in the sub-frame or at therear of sub-frame 1647. According to a variant on the electricitystorage unit can be stored centrally 1648 or at the rear of sub-frame1647. Tanks 1641, 1642 are once again provided in the main frame.

FIGS. 17A to C show yet another variant with fuel cell, wherein all thediscussed components of the drive means are located in the sub-frame.The fuel cell unit or storage capacity unit 1748 is more particularlysituated centrally in the sub-frame with a tank 1741, 1742 on eitherside thereof. The electricity storage capacity or fuel cell 1747 andcooling unit 1743 are further situated at the rear in the sub-frame.

FIGS. 18A to 18C show yet another variant with fuel cells andelectricity storage unit, wherein these components are distributed overelements 1847, 1848 and 1849 and 1850. Units 1849 and 1850 are situatedin the main frame, on two outer sides thereof. Unit 1848 is situatedcentrally in the sub-frame and unit 1847 is situated at the rear in thesub-frame.

According to another variant illustrated in FIGS. 19A to 19C, the mobileunit can be driven wholly electrically or wholly via fuel cells. In theembodiment of FIGS. 19A to 19C the components 1947, 1949, 1950 can allbe electricity storage units or all fuel cell units. Units 1949, 1950are situated in the main frame as far as possible toward the outsidebetween the front and rear wheels. Unit 1947 is situated at the rear inthe sub-frame.

Finally, FIGS. 20A and 20B show a further variant with one fuel cell2048 and two electricity storage units 2049, 2050. Storage units 2049,2050 are provided in the main frame, while fuel cell 2048 is provided inthe sub-frame. Tank 2041, 2042 are further provided on either side ofthe centrally mounted fuel cell 2048. Finally, the sub-frame is providedat the rear with a cooling unit 2043.

FIGS. 21(A)-(E) further illustrate another important variant, whereinthe larger wheels 2004 are provided at the front instead of at the rear,i.e. the side of the three-point lifting device 2013 in FIGS. 21(A)-(E).The small wheels 2004′ are then provided at the rear. The othercomponents of this embodiment resemble those of the embodiment of FIGS.1(A)-(E) and will not be discussed again in detail here. Similarcomponents are designated with the same reference numerals, with 2000added.

Mobile apparatus 2001 has a rotatable sub-frame 2003 so that thedriver/operator can select the travel direction or, in other words, canchoose which side functions as front side in which as rear side. Thedriver can herein position the articulated arm or the single lifting arm2010 on that side where it is most effective. The reason for opting tooperate with large wheels 2004 at the front may for instance be toreduce the ground pressure. In determined cases this may moreover havethe additional advantage that a greater steering angle of the steeredwheels is thereby possible. At higher speeds of the mobile apparatus itmay then be recommended to return the machine to the position with smallwheels at the front.

As illustrated in FIG. 21(B), the mobile apparatus can be embodied inaccordance with a variant such that the most steered wheels, the smallwheels 2004′, are on the rear side. It is also possible—see FIG.21(C)—that only the rear axle with small wheels 2004′ is steered andthat the front axle with large wheels 2004 is not steered.

Note that in yet another embodiment all wheels can be of the same size.

In order to ensure that the driver can choose between two possibletravel directions, a switch is for instance provided which switches thesteering wheel movement of all four wheels and/or of only the steeredwheels (see for instance the variant of FIG. 21(C)). FIG. 25(A) showsschematically how this switch in travel direction, or of front and rearside, and so also of steering direction, can be realized. Shown in thisfigure is a steering wheel 2501 which is coupled to a technical device,for instance an orbit roll 2502, which converts the rotating steeringsignal into an electrical/pneumatic or hydraulic signal. This signal isfor instance converted by a manipulator 2503, wherein manipulator 2503is adjusted using a switch 2504. This switch 2504 is typically arrangedclose to the driver's seat or where the driver sits or stands. Singlemanipulator 2503 can for instance be an electric relay, but can also bea pneumatic or hydraulic steering slide or valve. This manipulatortransmits the signal to an actuating member, here for instance apneumatic or hydraulic cylinder 2505. This can for instance also be anelectrically driven spindle which realizes the angular adjustment of thefront wheels and/or the rear wheels.

In the shown situation switch 2004 is in the rest position. Here thetravel direction is forward as indicated on the left in the figure, withthe front side on the side of the small wheels. At a switch-over forwardbecomes reverse, and the front side thus becomes the side with the largewheels.

According to another embodiment variant, the steering wheel can bereplaced by a joystick which will determine the steering angle of thewheels.

If the driver changes the travel direction via switch 2504, it is thenalmost essential in practice to switch operation of forward and reverse.The driver is after all accustomed to choosing between forward andreverse because there is a front and a rear side of the machine. Ifhowever these sides are switched, it is then recommended to also switchthe operation of forward and reverse in order to avoid confusion.

FIG. 25(B) shows schematically how this switch-over is effected. In theprior art apparatus a switch between forward and reverse 2508 istypically provided in the vicinity of driver 2508. This switch 2508 isfor instance on the right-hand joystick, or can be a foot pedal or evenmultiple foot pedals. This switch 2508 is likewise used to adjustmanipulator 2503. If the travel direction, and so front side and rearside, are now reversed, the travel direction of the motor 2507 will thenalso be reversed via manipulator 2503. In this way switch 2508 thuscontinues to retain its function, and forward is the direction which atthat moment is indicated as forward by switch 2504.

As illustrated in FIG. 22, it is likewise possible to position anattachment, such as for instance a mowing bar 2230, under the machinebetween the axles. In this way both the lifting device and the operatingarm are still available. Similar components are designated with the samereference numerals as in FIGS. 1(A)-(E), wherein 2200 is added.

If the operating arm is used as loading bucket or other attachment suchas a pallet fork 2311 (see FIG. 23) on the side of the large wheels, itis possible to place a counterweight 2314 in the quick change device2329. An example is shown in FIG. 23, wherein similar components aredesignated with the same reference numerals as in FIGS. 1(A)-(E),wherein 2300 is added. In this position it is also possible to use aloading bucket 2414 as counterweight as illustrated in FIG. 24, whereinsimilar components are designated with the same reference numerals as inFIGS. 1(A)-(E), wherein 2400 is added.

According to another embodiment variant (not shown), it is possible tomount a three-point lifting device only on the side of the small wheels,and in yet another embodiment variant it is possible to have athree-point lifting device at both the front and rear, wherein hydraulicconduits are available on each side for additional functions. Thislatter variant has the advantage that more attachments can be coupledsimultaneously to the machine.

In another further developed embodiment variant it is possible to havethe front wheels and the rear wheels operate on a narrower track. Ithereby becomes possible to also drive on narrow paths, or for instancebetween fruit trees or in vineyards. The driver can then preferablychoose between a normal width track or a narrower track. In anothervariant thereof it is possible to have the front axle operate at a trackwidth other than the rear axle. The advantage is that in this way onlyone wheel drives over the ground surface, and less damage is thereforecaused to the ground.

Finally, yet another variant consists of limiting the rotation of thesub-frame, or of fixing the sub-frame. This is possible with amechanical or hydraulic or other type of brake or by a mechanicallocking. This may for instance be useful in practice during mowing ofverges or trimming of hedges. The mowing bar or hedge cutters are herefixed to the outer end of the articulated arm or the loading bucket arm.The machine then moves forward at a determined speed. If no rotationlocking or brake is arranged, there is then the possibility that due toincreased resistance of the attachment—in a direction opposite to thetravel direction—the sub-frame will begin to rotate. This is thenprevented by a brake or a locking on the rotation device of thesub-frame.

The skilled person will appreciate that the present invention is notlimited to the above described exemplary embodiments, and that manyvariants can still be envisaged which fall within the scope of theinvention, the scope being defined solely by the following claims.

1-21. (canceled)
 22. A mobile apparatus, comprising a main frame displaceable on one or more displacing means; a sub-frame which is rotatable around a vertical axis and which is mounted on said main frame; said sub-frame comprising a driver's position, and a number of steering elements; an operating arm mounted on said sub-frame; and an automatically movable lifting device provided on said main frame, said lifting device being adapted to be connectable to an agricultural attachment; at least one motor for driving at least said one or more displacing means; wherein said operating arm comprises at least a first articulation connected pivotally to said sub-frame, a second articulation connected pivotally to said first articulation, and a third articulation connected pivotally to said second articulation; such that said first, second and third articulations can be folded against each other to transform said operating arm from an articulated arm to a folded single lifting arm.
 23. The mobile apparatus of claim 1, wherein said operating arm and said lifting device are positioned at opposite sides of the mobile apparatus.
 24. The mobile apparatus of claim 1, wherein said mobile apparatus has a front side and a rear side in relation to a driving direction; wherein said operating arm is positioned at said front side, and said lifting device is positioned at said rear side.
 25. The mobile apparatus of claim 1, wherein said mobile apparatus has a front side and a rear side in relation to a driving direction; wherein said operating arm is positioned at said rear side, and said lifting device is positioned at said front side.
 26. The mobile apparatus of claim 1, wherein said operating arm is attached to the sub-frame such that, when said operating arm is transformed into said folded single lifting arm, it can be placed in a low position with the operating arm extending downward, such that a driver, when positioned in said driver's position, has an unobstructed view looking into a travelling direction.
 27. The mobile apparatus of claim 1, wherein said one or more displacing means comprise forward displacing means and rearward displacing means, and wherein said operating arm extends over an axis of one of said forward displacing means and said rearward displacing means.
 28. The mobile apparatus of claim 1, further comprising a number of cylinders for operating said operating arm, wherein said number of cylinders comprises a lower cylinder connected to the sub-frame by means of an adjusting device, said adjusting device being configured to descend said first articulation further downward into a lowest position of the folded single lifting arm and to move the first articulation further upward in an uppermost digging position of the operating arm.
 29. The mobile apparatus of claim 1, wherein said one or more displacing means comprise two first wheels and two second wheels, and wherein said first, second and third articulations are foldable against each other between said first wheels.
 30. The mobile apparatus of claim 8, wherein said sub-frame is provided with an upwardly extending section between said first wheels, and wherein said first articulation is attached to said upwardly extending section.
 31. The mobile apparatus as claimed in claim 1, wherein the lifting device is a three-point lifting device.
 32. The mobile apparatus as claimed in claim 1, further comprising a power takeoff on the main frame, said power takeoff being coupled to said at least one motor, for driving an attachments.
 33. The mobile apparatus as claimed in claim 11, wherein the power takeoff and the lifting device are positioned at the same side of the main frame.
 34. Mobile apparatus as claimed in claim 1, wherein the at least one operating arm is mounted on the sub-frame for pivoting around a horizontal axis.
 35. The mobile apparatus as claimed in claim 1, wherein the at least one operating arm is mounted on the sub-frame for pivoting around a vertical axis.
 36. The mobile apparatus as claimed in claim 1 wherein the one or more displacing means are one of the following: wheels, caterpillar tracks, mechanical legs.
 37. The mobile apparatus as claimed in claim 15, wherein the mobile apparatus is provided with a pair of rear wheels and a pair of front wheels.
 38. The mobile apparatus of claim 1, wherein the mobile apparatus has a front side and rear side and a travel direction corresponding thereto, wherein the mobile apparatus further comprises a mechanism for reversing the travel direction, and hence the front side and the rear side.
 39. The mobile apparatus of claim 1, further comprising a switch configured to be operated by a driver for adjusting a travel direction of the mobile apparatus.
 40. The mobile apparatus of claim 18, further comprising a signal manipulator, said signal manipulator being coupled to the switch and to the steering elements for moving the mobile apparatus in the travel direction set by the driver using the switch.
 41. The mobile apparatus of claim 19, further comprising a forward/reverse switch, wherein the forward/reverse switch is coupled to the signal manipulator for moving the mobile apparatus in the travel direction set by the driver using the switch, taking into account the position of the forward/reverse switch. 